U.S. patent number 5,236,055 [Application Number 07/728,713] was granted by the patent office on 1993-08-17 for wheel with coaxial drive system mounted in the wheelhub field of the invention.
This patent grant is currently assigned to Canadian Aging & Rehabilitation Product Development Corporation. Invention is credited to Jules O. Legal.
United States Patent |
5,236,055 |
Legal |
August 17, 1993 |
Wheel with coaxial drive system mounted in the wheelhub field of
the invention
Abstract
A motorized wheel assembly is provided for a wheelchair in which
there is a seat for receiving the occupant attached to a vertical
shaft with a single central wheel mounted at the bottom of the
shaft for rotation about a horizontal axis transverse to the chair
and defining a direction of forward movement of the wheel forwardly
of the chair. On the shaft is carried a battery and control unit
for supplying power to the drive motor of the, wheel mounted on the
hub of the wheel. An outrigger frame includes a sleeve slidable on
the shaft and a plurality of arms extending outwardly from the
sleeve each arm carrying a castor wheel to prevent toppling of the
device. Steering is achieved by the feet of the user applied to the
outrigger frame to rotate the chair and the drivewheel about a
vertical axis. The wheel is of the motor in a hub design which is
achieved by providing a cylindrical housing surrounding the motor
with at least one annular bearing on the outer peripheral surface
of the housing carrying the rim of the wheel which directly
surrounds the housing. An output shaft at one end of the housing
drives the rim through a coupling extending around the housing.
Inventors: |
Legal; Jules O. (Manitoba,
CA) |
Assignee: |
Canadian Aging & Rehabilitation
Product Development Corporation (Winnipeg, CA)
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Family
ID: |
27100006 |
Appl.
No.: |
07/728,713 |
Filed: |
July 11, 1991 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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668866 |
Mar 13, 1991 |
5183133 |
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Current U.S.
Class: |
180/65.51;
180/65.6; 180/907; 310/67R |
Current CPC
Class: |
B60K
7/0007 (20130101); A61G 5/043 (20130101); A61G
5/1051 (20161101); B60L 15/2009 (20130101); B60L
50/52 (20190201); Y02T 10/7275 (20130101); B60L
2200/34 (20130101); Y02T 10/641 (20130101); B60K
17/043 (20130101); B60Y 2200/84 (20130101); Y02T
10/70 (20130101); Y02T 10/72 (20130101); B60L
2220/44 (20130101); Y02T 10/645 (20130101); B60K
2001/045 (20130101); B60K 1/04 (20130101); A61G
5/1072 (20130101); A61G 2203/14 (20130101); B60K
2007/0046 (20130101); B60L 2240/421 (20130101); B60L
2220/50 (20130101); Y02T 10/64 (20130101); B60L
2240/12 (20130101); Y10S 180/907 (20130101); A61G
5/1059 (20130101); Y02T 10/7005 (20130101); B60K
2007/0092 (20130101) |
Current International
Class: |
A61G
5/00 (20060101); A61G 5/04 (20060101); B60K
7/00 (20060101); B60K 1/04 (20060101); B60K
17/04 (20060101); B60K 001/00 () |
Field of
Search: |
;180/65.5,65.6,252,10,22,6.5,214,907 ;310/67R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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920950 |
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Dec 1954 |
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DE |
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2231207 |
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Mar 1973 |
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DE |
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3826933 |
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Feb 1990 |
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DE |
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WO91/01897 |
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Jun 1990 |
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WO |
|
2123362 |
|
Feb 1984 |
|
GB |
|
Primary Examiner: Focarino; Margaret A.
Assistant Examiner: Hurley; Kevin
Attorney, Agent or Firm: Battison; Adrian D. Ade; Stanley G.
Thrift; Murray E.
Parent Case Text
This is a continuation-in-part of application, Ser. No: 668,866,
filed Mar. 13th, 1991 and now issued as U.S. Pat. No. 5,183,133.
Claims
I claim:
1. A driven wheel assembly for providing motive power to an article
to which the wheel is attached, the wheel assembly comprising a
wheel tire for engaging the ground, a wheel rim on which the tire
is mounted for rotation about an axis of the wheel rim, a motor and
transmission assembly for driving the wheel, housing means
including a substantially cylindrical portion and an end face
within which the motor and transmission assembly is mounted, the
motor and transmission assembly having an output member extending
through the end face, rigid drive connection means for
communicating drive from the output member to the wheel rim for
driving the tire relative to the ground, a sleeve shaped portion of
the wheel rim coaxially surrounding the substantially cylindrical
portion of the housing means, and bearing means for supporting the
wheel rim the drive connection means and the output member as a
single unit for rotation relative to the housing means, wherein the
bearing means consists solely of an annular bearing positioned
between the cylindrical portion of the rim and the sleeve shaped
portion of the housing means and a second bearing smaller in
diameter than the annular bearing located between the output member
and the housing means, and wherein the tire is mounted directly
upon and in contact with the sleeve shaped portion of the wheel
rim.
2. The wheel assembly according to claim 1 wherein the housing
means projects axially outwardly from one end of the rim.
3. The wheel assembly according to claim 1 wherein the housing
means contains said motor, a reduction gear coupling mounted on an
end of the motor and a clutch member connected between the gear
coupling and the output member.
4. The wheel assembly according to claim 3 wherein the motor is
mounted in a portion of the housing means projecting outwardly from
the rim at said one end.
5. The wheel assembly according to claim 4 wherein a portion of the
housing means surrounding the motor is of larger diameter than the
portion projecting into the rim.
6. The wheel assembly according to claim 5 wherein the portion
projecting into the rim receives the reduction gear coupling and
the clutch member.
7. The wheel assembly according to claim 6 wherein the connecting
means is mounted between the motor and said portion extending into
the rim.
8. The wheel assembly according to claim 1 wherein the annular
bearing is located at an end of the rim remote from the output
member and wherein the output member comprises a shaft coaxial with
the rim and wherein the second bearing is located inside the
housing means between the housing means and the shaft.
9. The wheel assembly according to claim 1 wherein said drive
connection means comprises a disc formed integrally with the sleeve
shaped portion, the disc including an inner clamping portion for
closely surrounding and clamping the drive shaft and wherein there
is provided an end cap member clamped to the disc and extending
radially outwardly form the disc to a radial extent greater than
that of the sleeve shaped portion so as to clamp the ground
engaging member between an end rim of the sleeve and the end cap
member.
10. The wheel assembly according to claim 9 wherein the sleeve
shaped portion includes a portion thereof of greater diameter than
a first portion thereof adjacent the end cap and arranged to
receive the annular bearing radially inwardly thereof.
11. The wheel assembly according to claim 1 wherein the tire is
moulded from a self skinning foam material.
Description
The present invention relates to a drive wheel assembly with a
coaxial drive system at least partly mounted within a hub of the
wheel.
BACKGROUND OF THE INVENTION
Many different types of vehicles require a drive system which
provides power to one or more of the wheels of the vehicle. Such
vehicles designed for slow relatively low power usage such as
chairs for handicapped persons often include a motor directly
driving one of the wheels provided with power from a battery.
One of the problems of such chair designs is the unsatisfactory
nature of the wheel and motor construction which is extremely bulky
and thus complicates the construction of the device and reduces the
area available for storage of the battery or other equipment.
Attempts have been made to design an arrangement in which the motor
for driving the wheel is positioned within the hub of the wheel
since this can provide a very compact arrangement particularly
suitable for the design of a motorized chair. However a
motor-in-the-hub design can also be used in other designs of
motorized vehicles with significant advantages of compactness and
ease of operation.
Some designs have already been proposed for motor-in-the-hub wheel
drive arrangements but these are highly complicated and therefore
very costly to manufacture and it is believed that none is
commercially successful or has been manufactured on a commercial
scale. various proposals are shown in all U.S. Pat. No. 641,603
(Newman); 680,804 (Newman); 1,090,684 (Church); 1,172,456
(Hoadley); 2,608,598 (hawkins and more recent U.S. Pat. No.
4,021,690 (Burton). However, as stated above all these devices are
highly complicated leading to devices which cannot be manufactured
on a commercial scale.
SUMMARY OF THE INVENTION
It is one object of the present invention, therefore, to provide an
improved driven wheel asesmbly.
According to the invention, therefore, there is provided a driven
wheel assembly for providing motive power to an article to which
the wheel is attached, the wheel assembly comprising a wheel
peripheral member for engaging the ground, a wheel rim on which the
peripheral member is mounted for rotation about an axis of the
wheel rim, a motor and transmission assembly for driving the wheel,
housing means within which the motor and transmission assembly is
mounted, the motor having an output member, means for communicating
drive from the output member to the wheel rim for driving the
peripheral member relative to the ground, at least a portion of the
wheel rim coaxially surrounding a portion of the housing means, and
bearing means for supporting the wheel rim for rotation relative to
the housing means, the bearing means including an annular bearing
positioned between the portion of the rim and the portion of the
housing means.
With the foregoing in view, and other advantages as will become
apparent to those skilled in the art to which this invention
relates as this specification proceeds, the invention is herein
described by reference to the accompanying drawings forming a part
hereof, which includes a description of the best mode known to the
applicant and of the preferred typical embodiment of the principles
of the present invention, in which:
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view taken along a vertical symmetrical
plane of a motorized chair of a type showing one example for which
the driven assembly of the present invention is particularly
suitable.
FIG. 2 is a perspective view of the chair of FIG. 2.
FIG. 3 is a cross sectional view taken along the lines 3--3 of FIG.
1 showing the motor, gear box and clutch arrangement of a driven
wheel assembly according to the invention.
FIG. 4 is a view along the lines 4--4 of FIG. 3.
FIG. 5 is a view along the lines 5--5 of FIG. 3.
In the drawings like characters of reference indicate corresponding
parts in the different FIGURES.
DETAILED DESCRIPTION
The drive wheel assembly shown in FIGS. 3, 4 and 5 can be used with
various designs of vehicle, one example of which is shown in FIGS.
1 and 2.
The chair shown in FIGS. 1 and 2 comprises a seat element generally
indicated at 10 including a horizontal seat bottom 11 onto which
the occupant can sit so as to be supported by the seat bottom 11
with the posterior of the occupant at the rear of the seat bottom
and the legs of the occupant depending over a front edge 12 of the
seat bottom. At the rear of the seat bottom is mounted a seat back
13 carried on a suitable vertical support 14 with arms 15 and 16
connected to the seat back 13 and extending from the sides of the
seat back forwardly along the sides of the seat bottom in
conventional manner. The occupant can therefore simply enter the
seat element by backing onto the seat and sitting onto the seat in
the conventional manner without any further difficulties.
The seat element 10 is mounted upon a vertical shaft 17 coupled to
the underside of the seat bottom in conventional manner to provide
sufficient strength to accomodate the weight of the occupant
without breaking or significant flexing. The shaft 17 carries an
external screw thread. The shaft is threadably engaged into a cup
18 in the form of a cylindrical body having a closed lower end 19.
The cup 18 carries, at an open upper end 20, a plate 21 which
closely surrounds the shaft and which projects outwardly from one
side of the shaft to act as a support element for a battery pack 22
and a control unit 23 both of which are shown only schematically.
The cup 18 and the plate 21 are thus effectively integral. The cup
is clamped to the threaded shaft 17 by a nut 24 which can be
screwed down to clamp a washer 25 against the upper surface of the
plate 21 thus holding the seat element, the shaft, the plate, the
battery and the control unit as an integral item for a common
rotation about the vertical axis of the shaft. The closed lower end
19 of the cup 18 is attached to a bracket 26 carrying a first wheel
27.
The bracket 26 includes a horizontal upper plate 29 which couples
to a vertical plate 30 extending downwardly from one side of the
plate 29. The plate 30 as shown in FIG. 1 is bolted to a housing
assembly 31 of a drive motor and gear box generally indicated at
32.
As shown in FIG. 1, the main load of the seat and the occupant of
the seat is applied downwardly through the shaft into the housing
and into the wheel 27 for support of the occupant from the
ground.
In order to prevent toppling of the seat on the central wheel 27
there is provided an outrigger frame generally indicated at 60. The
outrigger frame includes a sleeve 61 surrounding the cup 18 and
slidable relative thereto in both the longitudinal and angular
direction to allow rotation of the outrigger frame relative to the
shaft and vertical movement of the outrigger frame relative to the
shaft and vertical movement of the outrigger frame relative to the
shaft and vertical movement of the outrigger frame relative to the
central wheel 27. The sleeve is coupled at its lower end to a dome
section 62 which extends over the wheel 27 and the bracket 26. The
dome can be simply and conveniently shaped and take little space at
the centre of the chair as shown in FIG. 2 in view of the compact
design of the motor and wheel arrangement.
Attached to the lower part of the dome are four arms 63 which
project outwardly from the dome at angularly spaced positions
around the periphery. The arms are cantilevered from the dome. Each
arm carries at its outer end a freely rotatable wheel 64 which is
non driven and roll simply across the ground. Three of the wheels
are castor wheels so that they can rotate to take up any required
direction about a vertical castor shaft (not shown). The fourth of
the wheels is fixed so its direction of forward movement lies along
the length of the respective arm. A circular hoop 65 is connected
to the arms at a position spaced outwardly from the dome 62 so as
to provide a convenient footrest for the feet of the occupant.
Between the underside of the plate 21 and the top of the sleeve 61
is provided a spring 66 acting as a compression spring pushing the
sleeve 61 downwardly relative to the shaft 18. The spring action
causes the outrigger frame to be pressed downwardly toward the
ground and the seat and wheel 27 to be drawn upwardly into the
dome. In a position of the device in which the seat is unoccupied,
therefore, the wheel 27 is lifted to a height above the lowermost
edge of the wheels 64 so that only the wheels 64 rest upon the
ground except when the seat is occupied.
In operation the occupant can simply enter the chair by the
conventional manner stepping backwards and seating on the seat
bottom. The feet of the occupant can then be lifted onto the
outrigger frame and particularly the hoop 65. A control unit 68 is
positioned on one of the arms of the chair for actuating the supply
of power from the battery 22 through the control unit 23 to the
motor 32. The occupant can therefore simply supply power to the
motor to drive the central wheel 27. The weight of the occupant
presses the wheel 27 downwardly and applies a significant downward
force onto the wheel so that it engages the ground with friction to
provide drive in the forward direction of the wheel. As described
above, the forward direction of the central wheel lies directly
forwardly of the chair. However the chair can be rotated relative
to the ground by the occupant simply pushing on the outrigger frame
with a relatively gentle force so that the outrigger frame remains
at a particular orientation to the ground but the chair and the
drive wheel rotate relative to the ground in order for the
outrigger frame to steer the chair. This allows the chair basically
to rotate about its own centre.
The mounting of the battery, control unit, motor, wheel and seat
all on the same integral support structure ensures that the device
can fully rotate and there is no connection other than the bearing
connection between the outrigger and the central support structure
of the chair. There is therefore no restriction on the amount of
rotation in one direction which can occur. The retraction of the
central wheel into the dome ensures that when the occupant is
removed, the device can simply be wheeled across the floor on the
castor wheels.
The housing 31 includes a first housing portion 55, an attachment
member 56 and a second housing portion 67. The first housing
portion 55 houses a motor generally indicated at 68. The motor is
shown only schematically but comprises a rotor disc 69 mounted
between two staters 70 thus providing a motor which has a very thin
axial length of the order of 0.75 to 1.0 inch and a diameter which
is very much greater than the axial length and can in one example
be of the order of 4 to 5 inches. Motors of this type are
commercially available and hence the details of the rotor and
stator will not be described as it will be apparent to one skilled
in the art. The stator elements are mounted on the housing 55. The
rotor is carried upon a motor shaft 71. The shaft is carried in the
first bearing 72 mounted in a dome portion 73 of the housing 65
projecting axially out from an otherwise flat end face of the
housing 65. A wire bushing 74 is provided on the end face of the
dome 73 to allow the entry of the coupling wires for communication
of drive power to the stator 70 of the motor.
A second end face of the housing portion 65 is defined by a flange
75 which projects radially outwardly from the housing so as to
surround the housing and form a coupling flange for connection to
the connecting member 56. The connecting member 56 thus includes a
cooperating flange 76 coextensive with the flange 75 to which it is
attached by suitable bolts. The coupling member 56 comprises a
structurally rigid body to provide the structural strength to carry
the motor on one side an to carry the gear box housing 67 on the
other side. The connecting member 56 is square in front elevation
as best shown in FIG. 5. The square block thus formed carries a
bearing 77 for the shaft 71 so that a splined end 78 of the shaft
can project outwardly from the connecting member 56 connection into
the gear box section to be described hereinafter.
The connecting member 56 is designed for universal coupling in that
it includes a plurality of blind tapped holes 79 arranged in
different planes so as to allow coupling from different directions.
Thus as shown in FIG. 3, each face of the rectangular block
includes a pair of holes 79 along a centre line and spaced
outwardly toward the outer edges. In addition each side face of the
block defined in the connecting member 66 includes a further hole
79 which projects axially as best shown in FIG. 5. This allows the
connecting member to be coupled to suitable supports for example
the support bracket 30 by different bracket arrangements.
The housing portion 67 houses a gear reduction transmission system
including a first gear assembly 80, a second gear assembly 81 and a
third gear assembly 82 each providing gear reduction so that the
total ratio of reduction is relatively high allowing the motor to
rotate at high speed while the wheel is driven at relatively low
speed. The gears are not shown in detail as these will be apparent
to one skilled in the art. The gear assemblies are mounted on the
inside surface of the housing 67 and each coupled to the next by a
shaft section. The housing 67 further contains a clutch/brake
assembly 83 which again is not shown in detail as this will be well
known to one skilled in the art. The clutch includes a pair of
clutch plates operable electrically to allow free wheeling of the
system when required. The clutch/brake 83 further includes a brake
assembly for connection of the wheel to the housing to act as a
brake if required to halt the vehicle on which the wheel is
mounted. The output from the clutch/brake 83 comprises a shaft 84
which projects out from an end face of the housing 67. The shaft 84
is mounted on bearings 85 carried on the end face of the housing 67
which is indicated at 88 and includes a recess 89 for receiving the
bearings 85.
The housing 67 includes a cylindrical portion extending from the
end plate 88 to a position closely adjacent the connecting member
56. A recess section 90 is formed adjacent the coupling member 56
and a flange 91 is defined at the end of the recess section with a
flange projecting radially inwardly for clamping to the outer face
of the connecting member 56. The flange 91 is clamped to the
connecting member by bolts (not shown) which extend through the
flange and into blind holes provides in the connecting member. The
bolts can be accessed through openings defined in the housing
extending through the end plate 88 and visible through the end
parts of the wheel described hereinafter so the openings are shown
in FIG. 4 at 92. This allows the assembly and disassembly of the
gear box by inserting a tool through the openings 92 to engage the
bolts and thus remove the gear box.
The shaft 84 projects outwardly from the end plate 88 a sufficient
distance for connection to an end disc 93 of the wheel assembly 94.
Thus the shaft includes a keyway 95 for receiving a set screw 96
passing through a boss 97 on the disc 93. The boss thus projects
axially beyond the disc so that the set screw can be accessed and
screwed radially inwardly and outwardly to engage the shaft. The
disc 93 simply forms a flat disc which is integrally connected to a
rim 98 of the wheel assembly. The rim defines an annular sleeve
projecting axially from the outermost edge of the disc coaxially of
the shaft 84. The rim 98 closely surrounds the cylindrical outer
wall of the housing portion 67. The rim 98 the housing 67 so as to
receive therebetween an annular bearing 100. The annular bearing
thus includes an annular inner race 101, an annular outer race 102
surrounding the inner race and a plurality of rollers or balls 103
therebetween. The annular bearing 100 is positioned at the end of
the cylindrical rim remote from the shaft 84 so that the bearings
100 and the bearings 85 provide sufficient support for rotation of
the rim about the axis of the shaft 84 on those bearings. The inner
race 101 is carried on the recess portion as a friction fit
thereon. The outer race is carried on the recess portion 99 as a
friction fit thereon.
At the edge of the recess portion 99 adjacent the connecting member
56 is provided an end flange 104 which surrounds the rim and
extends radially outwardly therefrom for combining an edge of a
tire 105 for engaging the ground and carried upon the rim. The tire
is clamped in place on the rim by an end cap 106 in the form of a
simple flat disc lying in contact with the disc 93 and clamped
thereto by bolts 107. The end plate 106 projects radially outwardly
beyond the cylindrical periphery of the rim so as to engage the
edge of the tire and to clamp the tire between the flange 104 and
the disc 106 so that it is held in place and prevented from
rotating relative to the rim.
Preferably the tire is of a type formed by molding in solid form
from a self skinning foam plastics material so that the tire is
solid and can be molded into the required shape including the
recesses for receiving the flange 104, the recess section 99 and
the disc 106.
The design by which the housing including the motor, gear
transmission and clutch is located at least partly within the hub
of the wheel is particularly effective in confined spaces and
allows designs of vehicles which avoid inefficient use of space in
the area around the drive system and the wheels.
In some embodiments (not shown) the clutch can be omitted thus
reducing the size of the gearbox section. In addition a brake, if
needed, can be applied to the motor armature since this allows the
brake to be smaller and locates it on the end of the motor outside
the gear box section.
Since various modifications can be made in my invention as
hereinabove described, and many apparently widely different
embodiments of same made within the spirit and scope of the claims
without departing from such spirit and scope, it is intended that
all matter contained in the accompanying specification shall be
interpreted as illustrative only and not in a limiting sense.
* * * * *